This invention relates to devices and techniques for dispensing medication and/or other treatment materials to hospital patients, and is especially directed to a medication dispensing cart which provides a nurse or other health care practitioner with access to each patient""s medication in a bin that has been previously prepared and filled for that purpose in a pharmacy facility.
Medication carts for distributing patient prescription drugs and other medication and treatment materials to hospital patients can be employed in hospitals, clinics, nursing homes and other health care facilities. In a typical design, the cart has a number of individual drawers, each with the medication for a respective hospital patient at a given hospital ward or floor. These carts are typically filled in the pharmacy department with the patients"" medicine, and then wheeled to the floor or ward. The typical medication cart can facilitate distribution of the medicine somewhat, but there remains a need to account for who may have access to a given patient""s medication and when such access occurred. This can be important in the case when a medication, e.g., digitalis in the case of heart patients, had to be xe2x80x9cborrowedxe2x80x9d from one patient""s drawer for the emergency use by another patient, thus leaving a deficit of that drug for the first patient. It is also important to ensure that the medication prescribed for a given patient reaches that patient and is not mistakenly administered to the wrong patient.
One proposal for a medicine cart with access limited to one drawer at a time is described in U.S. Pat. No. 6,170,929. In that cart, there are a number of individual trays that are carried on a conveyor inside the housing of the cart, and these can only be accessed, one tray at a time, at one position at the top of the cart, where there are locking access doors. A microprocessor controls the movement of the conveyor in response to a hand-held computer that is carried by the nurse. This particular cart does have significant limitations in that its bins are not removable, so they cannot be removed to take to the patient""s room for administration of the medicine, nor can the bins be pre-loaded at pharmacy and simply inserted into the cart. The need to load the cart by hand leaves room for human error in placing the drugs, syringes, bandages or other medication into the individual bins on the cart, as well as in the need for manual entry of patient and medication information into the unit.
It was desired to have a medical cart or similar medical dispensing station that facilitates pre-loading the patient medication bins by the pharmacist, and which minimizes the opportunity for human error when the medications are dispensed.
It is also desired to have the medical cart automatically bring the various bins up to a dispensing location on the cart one at a time, and to have an automatic bin-centering feature so that the bins do not collide with internal hardware inside the cart cabinet when the bins are being transported on the conveyor inside the cart.
Accordingly, it is an object of the present invention to provide a medical dispensing cart or equivalent dispensing station that avoids the drawbacks of the prior art.
It is another object to provide a medical cart that facilitates administration of medication to each of the patients in a given hospital ward or floor, with a minimum of complexity and without opportunity for human error.
It is still another object to provide a medical cart that can be easily loaded using patient medicine bins that have been pre-loaded at a pharmacy for the respective patients, and which can automatically transfer data concerning the contents of the bin and the identity of the patient for that bin to the data processor of the cart.
In accordance with an aspect of the present invention, an automated medication dispensing cart, has a cabinet or enclosure with a flat top surface work surface. There is at least one drawer opening in the front wall of the cabinet at a drawer position near the top of the cabinet. An on-board processor stores data concerning the contents of the various medicine bins inside the cart and controls operation of the bin conveyor mechanism. The processor includes display means and a keyboard, active screen, or other user access means to permit the user to enter information about the patient so that the user, to wit, a nurse, can access the patient""s medication within the dispensing cart. Within the cart there are a plurality of elongated medication bins, e.g., 24 to 35 bins, and internal conveyor means within cart cabinet or enclosure that support the bins and moves them, under control of the processor, along a predetermined pathway inside said cabinet. This can be a serpentine (folded) pathway so as to maximize the number of bins contained in the cart. There is a drawer position on this pathway aligned with drawer opening, and a drawer is located at this drawer position. Here, a slide member engages a respective one of the bins that happens to be located at the drawer position, and permits the user to pull the bin out from said conveyor means and to pushed it back in to return the bin to the conveyor means. The internal conveyor means includes a plurality of bin carriers that are spaced apart at intervals on the conveyor means, and which are transported along the folded pathway. Each of the bin carriers has structure that slidably mates with corresponding structure on the bins, so that the bins are supported on the conveyor means as they travel along the pathway but are permitted to slide out from the respective bin carriers when at the drawer position.
Preferably, each of the bins can be removed from the cabinet when the bin is at the drawer position with the drawer slide pulled out. The bin can be removed and put back into the drawer later or can be replaced with another bin from the pharmacy. In each case a coded device, that is a 2-D bar code symbol or other coded visual, RF, or magnetic symbol (i.e., a machine-readable code) is positioned on the bin, with the coded symbol containing data representing the contents of the bin and associated patient identification information. The cart includes a reader device at the drawer position for reading the coded symbol and for transferring data for each respective bin to the on-board processor, so that the processor can keep track of which bin is which on the conveyor, as well as what the contents arc for the bins. This facilitates accountability for the medications in the cart, and also makes it possible for a patient""s medication to be xe2x80x9cborrowedxe2x80x9d on an emergency basis, while at the same time the processor will note a shortage of the bin from which the medication had been borrowed so it can be replaced. The processor facility that permits borrowing can be enabled, limited, or blocked, at the option of a supervisory authority.
The bins can be loaded in an order that is determined by an algorithm so as to minimize the times for the bins to reach the access drawer position.
Preferably, the bins are configured to be removable from the drawer when in the drawer is opened. This can facilitate taking the bin directly to the patient with the set of medications for that patient. In a preferred embodiment, each the bin carriers has a pair of horizontal flanges facing one another along opposite sides of the carrier, and each said bin has a pair of elongated channels on opposite sides to slide onto the carrier flanges. This allows the bin to be held securely while traveling on the conveyor inside the enclosure, but also allows the bin to slide out for removal and replacement.
The conveyor pathway is preferably a closed, serpentine loop. The conveyor includes a drive web, e.g., a chain or belt traveling over wheels or pulleys that define the closed loop and the bin carriers are affixed onto this drive web. A gear drive motor drive propels the drive web, with the gear motor drive preferably being a 90-degree gear motor disposed at a back wall of the enclosure. This arrangement is remarkably compact. The gear motor drive includes a worm gear that prevents the conveyor from being advanced by hand when the drawer is pulled out, so only the one bin can be accessed at a time.
The serpentine pathway can leave space in the cabinet for an auxiliary drawer situated at or near the top, and which can be adjacent the removable-bin drawer. This contains an auxiliary (fixed) bin that does not travel along pathway, with the serpentine pathway bypassing the auxiliary drawer position.
In a preferred mode, the drawer slide includes a rear pusher arm at a distal end of the slide behind said the position of the bin carrier, and this rear arm is rotated by cam action to contact and push out the associated bin when the drawer is pulled out. There is also a front pusher arm at a proximal end of the slide in advance of the carrier and this front arm is also rotated by cam action to contact and push the associated bin back onto the carrier when the drawer is pushed back in. Both the rear and front arms are rocked out of contact with the associated bin when the drawer is in a fully closed position. There are front and rear cams operatively coupled to the front and rear arms, respectively, and a cam track affixed in the enclosure at the drawer position. The first and second cams respectively ride on this cam track when the drawer is pulled out and pushed in.
The web may be one or more continuous chains or alternatively one or more continuous belts of a durable synthetic material, such as polyethylene, polypropylene, vinyl, reinforced vinyl, Tyvek, or another suitable material.
The cabinet or enclosure preferably has casters or wheels to permit it to be pushed to desired locations on the floor or hospital ward. This can have other auxiliary features such as a lamp or light to facilitate reading of the prescription information for the patients or in completing the patient charts, and may have one or more built in IV pole. A waste container may also be incorporated. It is also possible to include a dispenser for towels, bandages, or other disposable materials.
The cart can be returned to the pharmacy for reloading after the medications are dispensed. Alternatively, a separate cart can be used for carrying pre-loaded bins to the hospital floor or ward, and a pharmacist can transfer the bins from the transport cart into the medication cart at the floor or ward. The pre-loaded bins can each have an identifying 2-D bar code symbol or other data-carrying symbol on it, which is automatically read when the bin is loaded into the medication cart, so that the cart""s internal processor can track the contents and location of each bin, as well as the identification of the patient that the medicine is intended for.
The on-board processor stores the patient and medication information for each bin, and also tracks the identification of the person accessing each bin. This provides a positive means of accounting for the administration of each medication.
In the preferred medication cart there are twenty-four removable bins or drawer compartments, which move along a conveyor that is formed of a parallel configuration of multiple pulleys and roller chains. On the drive chain(s), at spaced regular intervals, are bin carriers that are supported on bins that extend out from the chains. Access to any particular drawer bin is through a single electronically locked door or panel near the top of the front wall of the cabinet. When a doctor, nurse, or other authorized user needs access to a drawer containing the patient""s medication, the user provides his name or password and identifies the patient by name or room number. The conveyor system then moves the associated medication bin to the access point, i.e., drawer position, and releases the lock on the access mechanism, so that the authorized user can pull out the drawer slide and access this one bin only. At the time that the bin is accessed, the 2-D bar code that has been placed by the pharmacy department on the distal or back end of the drawer bin, is read by a scanner at that position, and the patient and bin content information is presented on the LCD screen of the on-board processor. This permits the authorized user to confirm that the bin is intended for that patient, and lists the contents of the bin on the screen. After the bin is replaced and the access drawer is closed, another drawer can be selected as desired, and the conveyor will bring the next desired bin to the access point or drawer position, and the access door is unlocked.
Preferably, the processor determines the shortest path to the next bin, and moves the conveyor in one direction or the other (forward or reverse) to reach the drawer bin in the shortest time. If the drawer is not immediately accessed, the access door can be automatically locked after a user-defined time period (e.g., 10 seconds). An audit trail is kept in the processor memory to identify who had access to any given drawer bin, and at what time access was made or attempted. This can be displayed on the LCD display or can be downloaded.
Preferably, the medicine bins are loaded in patient order, room order, or bed order, so as to minimize the time between stations on the conveyor, but this is not always necessary, and the bins can be loaded in other ways to optimize utilization.
The conveyor path is designed to maximize the number of drawer bins for the available volume inside the cart enclosure. The serpentine path also permits there to be a fixed drawer, preferably positioned at the top of the front wall next to the drawer for the removable bins. This drawer can be omitted to further increase the number of removable bins. This drawer can be employed either for larger bottles of multiple dose medication, such as a floor stock of liquid potassium, intended to be dispensed to many patients on the same floor or ward. The fixed drawer may also be used as a narcotic drawer, and require the input of an additional, secondary password or security code. A predetermined one (or more) of the removable bins can also be designated a narcotic bin and may require a special access code.
The conveyor track in this embodiment accommodates rather long pull-out bins, so the bins can be larger and longer than with other cart configurations. This allows the storage of larger bottles or containers of multiple dose medications.
The conveyor drive is a DC right-angle gearmotor, with a worm drive that prevents movement of the conveyor by manual pushing on a bin when the access door is open. The cart can be AC powered with battery backup, may be entirely AC powered, or may be entirely battery powered with plug-in recharging.
The cart can have an access mode for use when dispensing the medications to patients and also a loading or xe2x80x9cpharmacyxe2x80x9d mode. In the latter mode, input of a single password only is required for unlimited access to every bin in the cart.
Upon loading of the removable drawer bins in the pharmacy, the bar codes or other readable indicia are automatically read for each bin at the drawer position when the bin is inserted. The barcode scanner reads each bar code symbol when the cart is loaded in the pharmacy mode, and the patient and medication data contained in the symbol are stored in a database on the on-board processor. These data are at the same lime displayed on the LCD screen for verification that the proper patient drawer bin has been inserted into the cart. Later upon accessing the drawer in the access mode, the reader again reads the bar code symbol on the back of the bin when it reaches the drawer position, and the information therein is displayed on the LCD screen. The data base can be queried for access for the location of a certain medication, and the drawer bin containing this medication can be identified and accessed by an authorized user. This feature permits the nurse or other practitioner to xe2x80x9cborrowxe2x80x9d a medication for a patient on the nursing unit who needs a medication not present in his or her own drawer bin, this feature permitting the nurse to xe2x80x9cborrowxe2x80x9d the medication from another patient. The on-board processor can track the shortfall that results from this emergency borrowing, so that pharmacy can be contacted before the intended patient needs that drug or medicine. It is possible to communicate wirelessly with the pharmacy to alert them when such borrowing occurs, so a replacement medication can be sent up. The functionality that permits xe2x80x9cborrowingxe2x80x9d can be enabled, blocked, or limited, in accordance with hospital policy.
In a preferred configuration, the top of the cart has a generally flat ABS plastic work surface, with the touch screen LCD display situated in one corner. The bin access door and drawer slide are located at the upper left corner of the front wall, and the fixed drawer is located at the upper right corner.
The cart of this invention has the advantages of providing access in any drawer bin from the front of the cart without the nurse needing to stoop or bend. There is regulated access to one removable drawer bin at a time. Any of the bins can be given limited access based on user permissions. There can be multiple specific-access user identifications in addition to global access pharmacy identifications. The cart maintains an audit trail of all persons who accessed each drawer bin, including what persons had access, which drawer bins were accessed, and the time and date thereof. The audit trail may also include a list of medications removed at the time of drawer access. This list of medications may come from user input on the touch screen display, or from using the bar code scanner to identify these medications when removed. The drawer bins can be loaded on site, or can be loaded remotely (at pharmacy) and brought to the cart for loading. As each bin is accessed, the contents and patient identification are checked against the contents of the associated bar coded symbol and are displayed on the LCD screen.
With the bar code (or other coded symbol) capability, bar coded symbols or other readable indicia are placed on the individual drawer bin by the pharmacy department and are automatically read into the memory of the on-board processor when the bin is placed into the cart When the drawer bin is moved to the drawer position for access, the reader device again scans the patient and medication data provided for that bin, and this information is displayed on the LCD screen. This gives an additional check, and permits the floor or ward nurse to scan the names for the entire cart inventory, so as to make sure the correct medication bins have been installed in the cart. This also permits the nurse to scan medications for the entire cart to obtain xe2x80x9cborrowxe2x80x9d medication from a different patient drawer bin in urgent situations.
The cart can also be used for dispensing multiple medications (i.e., non-patient-specific items), bandages, salves, etc., in some of the bins, and in this case the bins can have internal dividers also. It is also within the scope of this invention for some of the bins to be non-removable with others being removable.
The on-board processor can be connected via an available computer cable to another computer for downloading audit trail information, or for uploading access and ID codes.
The cart of this invention allows access to only one removable drawer bin at a time, and provides access to each of the twenty-four drawers from a single pull out drawer at the top front of the cart.
The cart is preferably supported on casters so that it can be moved by the staff from room to room, and so that it can be taken to the pharmacy for reloading. However, it is entirely within the broad principles of this invention to provide a non-movable medicine dispensing cabinet that remains at a fixed station on the hospital floor.
An alternative embodiment can have an enclosure that extends upward, e.g., to a height of seven feet or more, with the drawer located at a position about three feet above the base of the enclosure. This may be provided with or without casters, and can contain twice the number of removable bins as in the first embodiment, e.g., ninety bins. Here, because the top is too high for use as a writing surface, a pull-out shelf can be provided adjacent to the drawer, i.e., just below it. The serpentine conveyor path extends both above and below the drawer position. A fixed drawer may optionally be included as well. Many other configurations can also be provided, i.e., double width, or having two or more fixed drawers.
The above and many other objects, features, and advantages of this invention will become apparent from the ensuing description of a selected preferred embodiment, which is to be considered in connection with the accompanying Drawing.